The present invention is related to glass processing and to glass processing with temperature sensing. More particularly, but not exclusively, the present invention is directed to through thickness temperature sensing during glass processing and methods of improving the quality of processed glass.
The efficient production of glass requires that the glass be at certain bulk temperatures during different stages of the production line, and the final properties of the glass product depend upon the processing temperatures and temperature history of the glass. For example, in the automotive industry, forming of glass is most effectively done when the glass is kept within a certain temperature range. In the case of tempered glass products, the stress locked into the product, which controls the strength and durability of the piece, also depends on the rate at which the product is quenched in a final step and on the temperature gradients established during quenching. The quenching rate may also influence, at least to some extent, the final shape of the piece. Hence there is a need for both general and specific knowledge of the glass temperature throughout the production process, and it is desirable to obtain this knowledge rapidly, efficiently, and without contacting the glass or otherwise disturbing the manufacturing process.
In some cases, knowledge of the bulk temperature or the surface temperature can be sufficient. In others, such as during the tempering step, spatial and temporal temperature gradients influence the final properties and shape of the glass piece and thus more precise knowledge could be beneficial. Unfortunately, great difficulties exist when making temperature measurements in glass, and these problems are particularly acute for dynamic conditions. For example, during typical quenching, a large quantity of cooling fluid impinges on the glass surface, creating numerous heat sources and heat sinks which compound the problems of passively determining the temperature of the glass.
Therefore a need exists for an improved method and apparatus for measuring temperature in glass products that has the ability to be non-contacting, real time, and through-thickness. There is also a need for a system and method that is economical and reliable even under the dynamic and extreme conditions experienced during quenching. There is also a need for a system and method that utilizes sensed temperature information to reduce waste and improve quality in a glass manufacturing process. One or more embodiments of the present invention address these or other needs.